The invention relates to implants for replacing at least part of a vertebra, for example after ablation of the vertebra.
The document EP-0 567 424-A1 discloses an implant of this kind comprising an intermediate body and two bearing parts adapted to bear against the vertebral plates of vertebrae adjacent the space left by a vertebra that has been removed. Each bearing part is assembled to one end of the intermediate body by a screw connection so that rotation of each bearing part relative to the body varies the total length of the implant. However, it takes a relatively long time to assemble the various components of the implant. What is more, given the number of parts capable of relative movement, adjusting the length of the implant is relatively complicated and takes a long time, which increases the duration of the surgery. Finally, manufacturing the implant entails defining a large number of accurate surfaces enabling relative movement of the parts. Manufacture is long and costly.
U.S. Pat. No. 5,723,013 relates to an implant for replacing a vertebra that is made up of two implant parts sliding one within the other. The two parts are in mutual contact through teeth enabling the length of the implant to be increased by distraction of the two parts. The length cannot be reduced, however. The length of the implant can be adjusted simply and quickly. However, fine adjustment of the length of the implant is not possible.